VITRIFICATION DEVELOPMENT AND EXPERIENCES AT FERNALD, OHIO

Vitrification of radioactive wastes products have proven to produce an extremely stable waste form. Vitrification involves the melting of wastes with a mixture of glass-forming additives at high temperatures; when cooled, the wastes are incorporated into a glass that is analogous to obsidian. Obsidian is a volcanic glass-like rock, commonly found in nature. A one-metric ton/day Vitrification Pilot Plant (VITPP) at Fernald, Ohio, simulated the vitrification of radium and radon bearing silo residues using representative non-radioactive surrogates. These non-radioactive surrogates contained high concentrations of lead, sulfates, and phosphates. The vitrification process was carried out at temperatures of 1150 to 1350 C. Laboratory and bench-scale treatability studies were conducted before initiation of the VITPP. Development of the glass formulas, containing up to 90% waste, will be discussed in the paper. The VITPP processed glass for seven months, until a breach of the melter containment vessel suspended operations. More than 70,000 pounds of good surrogate glass were produced by the VITPP. Experiences, lessons learned, and the planned path forward will be presented.